[GRASS-user] Strategies to Import Geological Cross Sections

[Phillip Allen]

Markus,

Thanks for shedding some light on this problem.

Yesterday I tried to work around it by extending my sql view with:

ST_Boundary(ST_Force3d(ST_Force2d(geom)))::geometry(MultiLineStringZ,32611)

so it would eliminate the M values (also I had a few z errors in the
cross-section) and convert the polygons to polyLines.  I then exported them
to shapefiles.  After the closed polyline-shapefiles were imported into
Grass I then converted them to faces using:
v.type input=xsec_c_lithL output=xsec_c_lithL_face from_type=line
to_type=face

This seemed to work so I would have an enclosed area to color.  But now I
cannot seem to color the cross-section faces?  It is just black.  I have a
text column with rgb values (255:255:255 format) but when I use it for "use
color for thematic mapping"  it keeps reporting
DBMI-SQLite driver error: error in sqlite3_prepare(): unrecognized token
error "'255:255:115"

What is odd is that I was able to color the polylines....I must admit that
I have never really had much luck thematically mapping vectors in Grass.

So now the question is how to color the thematically mapped cross-section
Faces?
I am using the latest version 7.0.3RC1.

regards,
Phil


On Thu, Jan 14, 2016 at 6:55 AM, Markus Neteler <neteler at osgeo.org> wrote:

> Hi,
>
> On Tue, Jan 12, 2016 at 11:37 PM, Phillip Allen
> <phillipjallen830 at gmail.com> wrote:
> > Hi all,
> >
> > I have digitized a few geological cross-sections each consisting of a 1
> > polygon & 1 polyline layer (representing lithology & faults
> respectively).
> > The layers were digitized in plan view with arbitrary coordinates in
> meters
> > and imported into PostgreSQL/PostGIS. I then created views using
> > ST_Translate(ST_RotateZ(ST_RotateX(ST_Translate(geom, ))) to correctly
> plot
> > the cross-section polygons & polylines in 3D space. One day I need to
> learn
> > how to multiply matrices so I can do it all in a single step!
> >
> > I just tried to import them into GRASS 7.0.3RC1 using v.in.ogr and got
> the
> > following error message:
> >
> > ERROR 1: Reading EWKB with 4-dimensional coordinates (XYZM) is not
> supported
> >
> > Can GRASS not import PostGIS 3D data?
>
> This error (given the fact that it is "ERROR 1" must come from OGR and
> not from GRASS GIS as we don't use numbers).
> Hence, ogr2ogr would likely report the same.
>
> > Is it the vertical Polygon with zero area topology problem?
> >
> > What other options do I have to get 3D-cross-section data into GRASS?
> >
> > I tried to use the ST_Extrude (to avoid topology problems) command in
> > PostGIS and Grass's v.in.ogr didn't like that either. Is there another
> way
> > to get 3D objects into GRASS?
>
> Which OGR version is installed? As soon as it works there I am
> confident that it also works with v.in.ogr.
>
> I see some discussion about the problem also here (random search result):
>
> https://lists.osgeo.org/pipermail/gdal-dev/2015-February/041056.html
>
> > I want to use v.hull on the vertical cross-sectional data and symbolize
> some
> > geochemical drill data in Grass's 3D viewer.
>
> IMHO it needs to be solved in OGR first (maybe it is in the latest
> version, I didn't verify).
>
> Best,
> Markus
>
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